Arkell.1956.Jurassic..

266 NORTH AFRICA
practically devoid of cephalopods, but it passes laterally into limestones,
marly limestones and marls, in which ammonites of the Italian Domerian
abound. Especially noteworthy are abundant Lytoceras fimbriatum
(Sow.) and allied species (Termier, 1936, pis. xx, xxi), Phylloceratids
(Juraphyllites spp.), Amaltheus, Pleuroceras and a swarm of Hildoceratidae
which might have come straight from the plates of Fucini and other Italian
authors: especially Arieticeras spp., Fuciniceras spp., Protogrammoceras
spp. and Catacoeloceras spp. (Termier, 1936, pi. xxii; Dubar, 1936;
Russo, 1936; Verlet & Roch, 1940, pp. 69-70, 73-6). Amaltheids have not
been found in the High Atlas (Dubar, 1936, p. 223). The dolomite facies
of Morocco compares closely in lithology and fauna with the Grey Limestones
of the southern Alps (Dubar & Termier, 1932).
LOWER PLIENSBACHIAN
The Ibex Zone is indicated by Liparoceras gallicum Spath (= bechei
d'Orb. non Sow.) (Gardet & Gerard, 1946, pi. i, fig. 10, improperly put
in the Domerian), and the Jamesoni Zone by Tropidoceras masseanum
(d'Orb.) and allied spp. and Polymorphites sp. (Termier, 1936, p. 1270;
Russo, 1936; Dubar, 1938a). Evidence reported from the Figuig area
consists of Platypleuroceras brevispinum (Sow.) and Crucilobiceras muticum
(d'Orb.) and some allied species (Verlet & Roch, 1940, pp. 73-4,
misplaced in the Domerian).
SINEMURIAN
Various species of Arnioceras and Oxynoticeras have been recorded
(Dubar, 1932, 1943; Termier, 1936, p. 1269; Verlet & Roch, 1940,
pp. 69-70, 72), and two Sinemurian ammonites have been figured by
Daguin (1926, pi. v) from Jebel Ayachi in the High Atlas, but unfortunately
without peripheral views or whorl-sections, which renders them
unidentifiable. The upper figure appears to be correctly named as
'Asteroceras' cf. brooki (Sow.), but the lower figure, in the opinion of
Dr D. T. Donovan (in lit.), is more likely to be an Arnioceras and no
earlier than Turneri Zone. Cf. turneri is recorded by Dubar (1943).
Beneath the Sinemurian ammonite beds near Figuig are dolomitic limestones
up to 200 (or 300 ?) m. thick, with brachiopods, resting on unfossiliferous
limestones.
? HETTANGIAN
Pink dolomites with Cardinia ? at the base may be Hettangian, but no
Hettangian ammonite is yet known from North Africa.
THE RIF
The Rif proper consists of the bow-shaped range already described
(p. 258), parallel to the coast, and made up chiefly of thrust sheets of
Triassic dolomite and Palaeozoic rocks (Fallot, 1937). To the south a
http://jurassic.ru/